This invention relates to information storage devices including magnetic disks. To ensure antiseptic conditions, such disks may be permanently enclosed within a disk drive. However, it often is advantageous to house a disk in a removable cartridge, with many such cartridges usable interchangeably on a single disk drive.
While removable disk cartridges no doubt enhance the utility of a single disk drive, they also raise problems not encountered when using permanently enclosed disks. For example, when outside the drive a cartridge must be sufficiently tight to prevent entry of dust, aerosols, and other foreign matter. Direct human contact must be prevented, since fingerprints can damage the disk. Preferably, the cartridge holds the disk firmly, to cushion it against damage, even if the cartridge is accidently jostled or dropped. Yet when loaded into the drive, the cartridge must open sufficiently to free the disk for movement and expose the disk to the signal read and write means (transducer) mounted in the drive. The cartridge must be capable, repeatably, of accurately positioning the disk upon insertion into the drive. Finally, it is desirable to reduce the space needed for storing cartridges, and this necessitates reducing the cartridge thickness or axial dimension.
Prior art devices to counter particulate exposure include a cartridge having a transducer access port, such port being normally closed, but opened by a probe or other means in the drive when the cartridge is inserted. This approach is shown in U.S. Pat. No. 4,412,260 to Stricklin et al. granted Oct. 25, 1983. In U.S. Pat. No. 3,975,768 to Jacque et al. granted Aug. 17, 1976, the drive has a wedge element 46 which forces top wall 42 and bottom wall 41 apart from one another as the cartridge is inserted.
To achieve positioning repeatibility, and also to protect against shock, prior art devices attempt to maintain the disk stationary relative to the cartridge when outside the drive. In the Stricklin patent, top and bottom walls 32 and 34 are biased outward to frictionally maintain the hub stationary within the cartridge. Upon loading, the hub is compressed by the cartridge loader in the drive to free the disk, as seen in FIG. 13. U.S. Pat. No. 4,394,700 to Edwards, granted July 19, 1983 shows a plurality of levers 72 biased into contact against the disk hub by coil springs 90. When the cartridge is inserted, release pins push levers 72 against the force of springs 90 to release the hub for rotation. While such frictional mounting is effective in keeping the hub and disk stationary relative to the cartridge, any force due to shock (for example from dropping the cartridge) is transmitted to the disk across the clamped juncture of the disk and hub. This can cause the disk to shift radially relative to the hub and destroy the centering capability.
Cartridge designs frequently involve complex head access door opening and closing mechanisms which usually are compatible with either a linear actuated head or a rotary arm mounted head, but not both. Such mechanisms are prone to wear, generate potentially harmful particles due to such wear, and require increased thickness of the cartridge.
It is an object of this invention, therefore, to provide a cartridge of simple and reliable construction which, when removed from a disk drive, protects its disk from contamination from dust, aerosols and human contact, and maintains its disk stationary without the transfer of undue shock forces through the disk/hub interface. It is a further object of the invention to provide convenient head access for both linear actuated and rotary actuator-mounted heads. Yet another object of the invention is to provide a means for continually urging the cartridge sections or covers together and for maintaining their precise alignment.